# Isotropy vs Number Challenge

The clearest difference is in-app purchases: Number Challenge at none against Isotropy's 1. Isotropy's advantage is ads (none vs shown) and iOS requirement (6.0 vs 13.0). On price and device support there is nothing between them.

Both are free to download. Isotropy sells 1 one-off in-app purchase. Number Challenge asks for nothing beyond the download.

## The numbers

| Metric | Isotropy | Number Challenge |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Monetization | Free with in-app purchases | — |
| Size | 72 MB | 73 MB |
| Requires iOS | **6.0** | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Dmitriy Prikhodko](https://appshunter.io/developer/558164332) | [OPTOELECTRONICS FUTURE LTD](https://appshunter.io/developer/1843235123) |

## What reviewers say

### Isotropy

[App page](https://appshunter.io/ios/app/isotropy/id992819687)

A fast-paced puzzle game where players must quickly identify and tap the unique item among 100 identical ones within a strict time limit. Challenge yourself to find as many differences as possible in this addictive test of observation.

**Highlights:** Identify unique item, 10-second time limit, Fast-paced gameplay, Observation challenge, High replayability

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads | $1.99 | one-time |


### Number Challenge

[App page](https://appshunter.io/ios/app/number-challenge-brain-game/id6757562508)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Isotropy free?

Isotropy is free to download, with in-app purchases available.

### Is Number Challenge free?

Number Challenge is free to download, with no in-app purchases.

### Do Isotropy or Number Challenge have ads?

Number Challenge shows ads; Isotropy does not.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*